hi there i installed the second hard disk SATA Hard Drive 160Gb Seagate 7200.7 ST3160023AS with no problems on my dell dimension 5000 its coming up as a C drive so do i have formatt it to windows or do i just leave it the way it is the Drive has been fdisked and formatted to NTFS already for OS i want to use it with the hard disk i have already to install programs on it as my hard disk is nearly full any advice.

Take a look at how your computer sees your drives by going to Control Panel -> Administrative Tools -> Computer Management -> Disc Management to be sure your boot order and disc labels are correct.
You have a lot of choices, but you cannot have the Dell Boot on both drives.
Most find it wise to use one drive for operating system and programs, and the second for data and operations related to the installed software.

so does that mean if i wanted to install a program i would have to install it on my existing hard drive which is F/Program Files/????? so i Can.t use the second hard drive.